Dear Dhanush-Kumar,
Good day! Thank you for posting to Microsoft Community. We are happy to help you.
As per your description, it seems that you are having issue removing multiple Microsoft logged account from Safari browser.
If the understanding above is right, considering that our category mainly focuses on general queries about Microsoft 365 and Office, for issue related to Safari, we may have limited resources and knowledge to help you further, we'd recommend you refer to Apple Support for more dedicated support.
Meanwhile, please check if accessing Microsoft portal and click on each account to forget can help.
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We hope the above can help. If the understanding above is not consistent with yours, please feel free to post back and point that.
Your understanding and patience will be highly appreciated. We hope that you are keeping safe and well!
Thanks for your cooperation.
Sincerely,
Rhoda | Microsoft Community Moderator